Modelling GNSS-observed seasonal velocity changes of the Ross Ice Shelf, Antarctica, using the Ice-sheet and Sea-level System Model (ISSM)
<p>The flow speeds of floating ice shelves around the Antarctic Ice Sheet exhibit clear intra-annual variability. However, the drivers of this variability remain poorly understood. Here, we present three new velocity datasets from Global Navigation Satellite System (GNSS) stations on the Ross...
| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2025-01-01
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| Series: | The Cryosphere |
| Online Access: | https://tc.copernicus.org/articles/19/107/2025/tc-19-107-2025.pdf |
| _version_ | 1826883623877345280 |
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| author | F. Baldacchino F. Baldacchino N. R. Golledge M. Morlighem H. Horgan H. Horgan H. Horgan A. V. Alevropoulos-Borrill A. Malyarenko A. Malyarenko A. Gossart D. P. Lowry L. van Haastrecht |
| author_facet | F. Baldacchino F. Baldacchino N. R. Golledge M. Morlighem H. Horgan H. Horgan H. Horgan A. V. Alevropoulos-Borrill A. Malyarenko A. Malyarenko A. Gossart D. P. Lowry L. van Haastrecht |
| author_sort | F. Baldacchino |
| collection | DOAJ |
| description | <p>The flow speeds of floating ice shelves around the Antarctic Ice Sheet exhibit clear intra-annual variability. However, the drivers of this variability remain poorly understood. Here, we present three new velocity datasets from Global Navigation Satellite System (GNSS) stations on the Ross Ice Shelf collected between early 2020 and late 2021 and show that they have two distinct peaks observed in austral summer and austral winter. These measurements do not appear to be consistent with the yearly cycle of sea surface height, which has previously been identified as a possible driver. We investigate the potential role of basal melt variability in ice flow speed and use the Ross Ice Shelf as a test bed. First we identify the regions where changes in melt would have the largest influence on ice speed at our GNSS sites using automatic differentiation. We then apply idealized sinusoidal perturbations to modelled basal melt rates at these specific locations to identify what magnitude of variability is needed to match the GNSS-observed changes in ice speed. We show that, while very local perturbations in basal melt can have a significant impact on ice flow speed, the amplitude of the perturbation required to match observations is significantly higher than expected, which may indicate that these perturbations are not realistic. We suggest that a combination of external forcings and internal mechanics may be needed to reproduce the observed intra-annual velocity variation at all the GNSS sites.</p> |
| first_indexed | 2025-02-17T03:48:22Z |
| format | Article |
| id | doaj.art-ace879b16de4481db4c740b241dfefdd |
| institution | Directory Open Access Journal |
| issn | 1994-0416 1994-0424 |
| language | English |
| last_indexed | 2025-02-17T03:48:22Z |
| publishDate | 2025-01-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | The Cryosphere |
| spelling | doaj.art-ace879b16de4481db4c740b241dfefdd2025-01-10T11:36:12ZengCopernicus PublicationsThe Cryosphere1994-04161994-04242025-01-011910712710.5194/tc-19-107-2025Modelling GNSS-observed seasonal velocity changes of the Ross Ice Shelf, Antarctica, using the Ice-sheet and Sea-level System Model (ISSM)F. Baldacchino0F. Baldacchino1N. R. Golledge2M. Morlighem3H. Horgan4H. Horgan5H. Horgan6A. V. Alevropoulos-Borrill7A. Malyarenko8A. Malyarenko9A. Gossart10D. P. Lowry11L. van Haastrecht12Te Puna Pātiotio, Antarctic Research Centre, Te Herenga-Waka, Victoria University of Wellington, Aotearoa, New ZealandInstitute of Geodesy, Graz University of Technology, Graz, AustriaTe Puna Pātiotio, Antarctic Research Centre, Te Herenga-Waka, Victoria University of Wellington, Aotearoa, New ZealandDepartment of Earth Sciences, Dartmouth College, Hanover, NH 03755, USATe Puna Pātiotio, Antarctic Research Centre, Te Herenga-Waka, Victoria University of Wellington, Aotearoa, New ZealandLaboratory of Hydraulics, Hydrology and Glaciology (VAW), ETH Zurich, Zurich, SwitzerlandSwiss Federal Institute for Forest, Snow and Landscape Research (WSL), Birmensdorf, SwitzerlandTe Puna Pātiotio, Antarctic Research Centre, Te Herenga-Waka, Victoria University of Wellington, Aotearoa, New ZealandTe Puna Pātiotio, Antarctic Research Centre, Te Herenga-Waka, Victoria University of Wellington, Aotearoa, New ZealandSchool of Earth and Environment, Te Kura Aronukurangi, University of Canterbury, Te Whare Wānanga o Waitaha, Ōtautahi, Christchurch, New ZealandTe Puna Pātiotio, Antarctic Research Centre, Te Herenga-Waka, Victoria University of Wellington, Aotearoa, New ZealandDepartment of Surface Geosciences, GNS Science, Lower Hutt, New ZealandTe Puna Pātiotio, Antarctic Research Centre, Te Herenga-Waka, Victoria University of Wellington, Aotearoa, New Zealand<p>The flow speeds of floating ice shelves around the Antarctic Ice Sheet exhibit clear intra-annual variability. However, the drivers of this variability remain poorly understood. Here, we present three new velocity datasets from Global Navigation Satellite System (GNSS) stations on the Ross Ice Shelf collected between early 2020 and late 2021 and show that they have two distinct peaks observed in austral summer and austral winter. These measurements do not appear to be consistent with the yearly cycle of sea surface height, which has previously been identified as a possible driver. We investigate the potential role of basal melt variability in ice flow speed and use the Ross Ice Shelf as a test bed. First we identify the regions where changes in melt would have the largest influence on ice speed at our GNSS sites using automatic differentiation. We then apply idealized sinusoidal perturbations to modelled basal melt rates at these specific locations to identify what magnitude of variability is needed to match the GNSS-observed changes in ice speed. We show that, while very local perturbations in basal melt can have a significant impact on ice flow speed, the amplitude of the perturbation required to match observations is significantly higher than expected, which may indicate that these perturbations are not realistic. We suggest that a combination of external forcings and internal mechanics may be needed to reproduce the observed intra-annual velocity variation at all the GNSS sites.</p>https://tc.copernicus.org/articles/19/107/2025/tc-19-107-2025.pdf |
| spellingShingle | F. Baldacchino F. Baldacchino N. R. Golledge M. Morlighem H. Horgan H. Horgan H. Horgan A. V. Alevropoulos-Borrill A. Malyarenko A. Malyarenko A. Gossart D. P. Lowry L. van Haastrecht Modelling GNSS-observed seasonal velocity changes of the Ross Ice Shelf, Antarctica, using the Ice-sheet and Sea-level System Model (ISSM) The Cryosphere |
| title | Modelling GNSS-observed seasonal velocity changes of the Ross Ice Shelf, Antarctica, using the Ice-sheet and Sea-level System Model (ISSM) |
| title_full | Modelling GNSS-observed seasonal velocity changes of the Ross Ice Shelf, Antarctica, using the Ice-sheet and Sea-level System Model (ISSM) |
| title_fullStr | Modelling GNSS-observed seasonal velocity changes of the Ross Ice Shelf, Antarctica, using the Ice-sheet and Sea-level System Model (ISSM) |
| title_full_unstemmed | Modelling GNSS-observed seasonal velocity changes of the Ross Ice Shelf, Antarctica, using the Ice-sheet and Sea-level System Model (ISSM) |
| title_short | Modelling GNSS-observed seasonal velocity changes of the Ross Ice Shelf, Antarctica, using the Ice-sheet and Sea-level System Model (ISSM) |
| title_sort | modelling gnss observed seasonal velocity changes of the ross ice shelf antarctica using the ice sheet and sea level system model issm |
| url | https://tc.copernicus.org/articles/19/107/2025/tc-19-107-2025.pdf |
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